All kegerators will start depositing beer stone on the inside of the beer lines from the very first keg. Beer stone is actually a lime deposit that comes from the beer. It slowly deposits on the inside of the beer line and will eventually flake & crack. Once this happens, the excessive roughness on the inside of the beer line will cause foaming. Beer stone is not caused by a lack of cleaning or by bad beer – it’s a natural deposit. And although there are commercial cleaners designed to remove beer stone, the beer line in a home kegerator is so short and inexpensive that the easiest solution is to just replace the line every 2 – 3 years.